1. Field of the Invention
The present invention relates to a method for manufacturing an array plate of hydrophilic and hydrophobic regions based on semiconductor manufacturing processes and a method for manufacturing a biochip by immobilizing biomolecules on the array plate.
2. Description of the Related Art
According to a conventional method for manufacturing a nucleic acid array plate including hydrophilic and hydrophobic regions, microdroplets of reactant solution spread by means of a piezoelectric pump can be migrated onto separate binding sites on the array plate due to a difference in surface tension between the hydrophilic and hydrophobic regions.
In particular, as illustrated in FIG. 1, the conventional method for manufacturing the nucleic acid array plate involves: (a) coating a support surface with a positive or negative photoresist which is subsequently exposed to light and developed to create a patterned region of a first exposed region; (b) reacting the first exposed region with a fluoroalkylsilane to form a stable fluoroalkylsiloxane hydrophobic matrix on the first exposed region; (c) removing the remaining photoresist to form a second exposed region; and (d) reacting the second exposed region with a hydroxy or aminoalkylsilane to form functionalized hydrophilic binding site regions.
Alternatively, as illustrated in FIG. 2, the nucleic acid array plate may be manufactured by: (a) reacting a support surface with a hydroxy or aminoalkylsilane to form a functionalized hydrophilic support surface; (b) reacting the support surface from step (a) with o-nitrobenzyl carbonyl chloride acting as a temporary photolabile blocking agent to provide a photoblocked support surface; (c) exposing the photoblocked support surface of step (b) to light through a mask to create unblocked areas on the support surface with unblocked hydroxy or aminoalkylsilane; (d) reacting the exposed surface of step (c) with perfluoroalkanoyl halide or perfluoroalkylsulfonyl halide to form a stable hydrophobic (perfluoroacyl or perfluoroalkylsulfonamido)allyl siloxane matrix; and (e) exposing the remaining photoblocked support surface to create patterned regions of the unblocked hydroxy or aminoalkylsilane as functionalized hydrophilic binding site regions.
In practice, however, it is difficult to control the thickness of the molecular layer, which is measured in tens of angstroms, using these methods for manufacturing nucleic acid arrays. Moreover, the strength of the thin molecular layer made using these methods is weak. Additionally, since the molecular layer is thin and transparent, it is difficult to distinguish the hydrophilic and hydrophobic regions of the molecular layer from one another for sample applying through a nozzle. It is also difficult to automate pattern detection by a detector system. In addition, the molecular layer is formed of materials which are unusual in the manufacture of semiconductor devices, and it is difficult to establish an alignment key for the exposure of such a molecular layer according to general semiconductor manufacturing processes.